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Experimental Measurement of the Effects of Acquisition Parameters on DAS Data Quality
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
Distributed Acoustic Sensing (DAS) is a seismic acquisition method that uses a fibre-optic cable as a sensor. A DAS amplitude measurement involves measuring the difference in the phase of the backscattered light between two positions on the fibre separated by a distance called the gauge length. Each phase measurement is the result of sampling the phase of a shorter section of the fibre using a window whose shape is that of the amplitude envelope of the transmitted laser pulse, often approximated as a Gaussian. As a result of this methodology DAS data has a distinct response, best viewed in the wavenumber domain. The response, in-turn, means that data quality varies significantly based on the acquisition parameters employed. In this paper we show results of the same vertical seismic profile acquired using a variety of different pulse and gauge lengths. The results agree well with theory and demonstrate the importance of the correct choice of DAS acquisition parameters.